structured_logging.py

import datetime
import json
import logging
from logging.handlers import RotatingFileHandler


class JsonLineFormatter(logging.Formatter):
    def format(self, record: logging.LogRecord) -> str:
        payload = {
            "ts": datetime.datetime.now(datetime.timezone.utc).isoformat(),
            "level": record.levelname,
            "logger": record.name,
            "message": record.getMessage(),
        }
        if hasattr(record, "event"):
            payload["event"] = getattr(record, "event")
        if hasattr(record, "meta"):
            payload["meta"] = getattr(record, "meta")
        return json.dumps(payload, ensure_ascii=True)


def configure_logging(log_file: str = "awareness.log", level_name: str = "INFO") -> logging.Logger:
    logger = logging.getLogger("awareness")
    if logger.handlers:
        return logger

    level = getattr(logging, (level_name or "INFO").upper(), logging.INFO)
    logger.setLevel(level)

    file_handler = RotatingFileHandler(log_file, maxBytes=1_048_576, backupCount=3, encoding="utf-8")
    file_handler.setLevel(level)
    file_handler.setFormatter(JsonLineFormatter())

    console_handler = logging.StreamHandler()
    console_handler.setLevel(level)
    console_handler.setFormatter(logging.Formatter("[%(levelname)s] %(message)s"))

    logger.addHandler(file_handler)
    logger.addHandler(console_handler)
    logger.propagate = False
    return logger


def log_event(logger: logging.Logger, level: int, event: str, **meta: object) -> None:
    logger.log(level, event, extra={"event": event, "meta": meta})